Plasma shields might be a reality for spaceships. Spacetravel exposes astronauts to high level of radiation (such as protons in solar wind), that is normally deflected by Earth magnetic field and atmosphere.
So, to protect astronauts, we could surround the ships with a bubble of plasma and deflect those nasty charged particles

Also, you might be interested to know that plasma can be used to make windows, a plasma window can be passed through by solid objects and light, but it can effectively form a barrier to keep, let's say the atmosphere of your spaceship on one side and the vacuum of space on the other. Translated: Star Trek-type force fields !http://en.wikipedia.org/wiki/Plasma_window